Amflector system



p 1 E. R. GILL, JR 2,906,884

AMFLECTOR SYSTEM 2 Sheets-Sheet 1 Filed Feb. 2, 1956 26 I MI I T 1 lg-INVENTOR l mi BY 14m. Lqffom 4/ 4e ATTORNEY Wig. 3. M 9% f4 Sept. 29,1959 E. R. GILL, JR 2,906,884

AMFLECTOR SYSTEM Filed Feb. 2, 1956 2 Sheets-Sheet 2 INVENTOR ATTORNEYshowing anothermodified cireuit;

United States Patent Oflfice 2,906,884 Patented Sept. 29, 1959 2306334AMFLECTQKSYSTEM Eawin R: Gill;- 112, Hiddenhnrst; (solemn Station, NY.

Application February-Z, 1956, Senal' N 56 3,026 ironin "(elf-250 213This.=inventionrelates to a device -for simultaneously reflecting andamplifying the intensity er light.

- of electrons, increase the intensity of the electron beam :to obtainan amplified electron beam and transform the amplified electron beaminto an amplified'light beam of increased intensity of brightness.However, the simultaneous amplification of the" light beam and thereflecting-thereof back-in the direction of its source has not been.previously proposed,-nor has this phenomenon been utilized in, practicalillumination or other practical uses.

-It is an objectbf-thepre'sent invention to provide a combination lightbeam amplifierand reflector, herein called an amflector.

It is a furtherobject of the present invention'to pro vide an amflectorwhich amplifies a beam 'of'light and reflects it back in the directionofits source.

Itlis 'astill further object of the resent invention-to provide anamplifier reiiector'for lightvvhich'tr'ans'forms a' beam ofllightinto"a'be'a"rnof 'electro'nsfincreases the intensity "of the electronbeam, transforms-the amplified electron beam into'an amplifiedilightbea'rn 'vvhich'is reflected back With further"arripli'fication"to"yielda'refiected amplified"light"bea'rn. 4

in is astilhfurthr objectbf'thepresent inventionto provideanainflector'vvhichtransformsafbeam of light into a beam of electrons,{increases theinte'nsity of the electronbearn, reflectsfthe electronsback with further amplification, and transformsftl're reflectedamplified electron beam into an amplified light beam.

It is a still further obiect of"thef'present invention to provide anarnflector which mayb'euse'd'for'purposes of room illuminationutiiizing'reflected amplified light.

"It is astill 'further object of "the present invention to "'pro de'anamflector which maybe used in conjunction wi'th h ghway signs. vOthefrbbjects and the naturea'n'd-advantagesof'the instant invention 'will be apparent' from the following description taken "in conjunction-With the accompanying "drawings, wherein: p p

Fi'g. l -is a'diagramrnatic sectional view of the am-Figf'Ziisarliagrammatic' sectionalview of the amfiector showing amodifiedfcircnit; I

Eig. 3'Fis a diagrammatic; sectional viewof the amflector fied form ofarnflector showinganother modified C11:

'iiu it; and

Fig. 8 isaperspective view-of a highway sign utilizing- In its preferredembodiments, thepresent'invention pro vides an amflector of laminatedconstruction Which is composed of extremely thin, superimposed laminae.

The term amflector as used in this specification and claims refers to adevice vvherein';light is simultaneously amplified and reflected. Theamplified light itself may be reflected asin Figs. l-3, or themultiplied electrons may be reflected and then-converted to amplifiedlight asin Figs. 57. I 4 I 7 Referring particularly to Figs. 1 3, thenumeral10 refers to a transparent or translucent'larnina orlayercontaining active material that fluoresces when bombarded withelectrons, thereby'tran sforming the electrdrisin'to a light ray. Thetransparent lamina'10ma'y be inade of glass orplasticcontainingthe-fluorescent material. Such fluorescent glassesandplastics are commercially available and are described in detail in'DeMents book 'entitled Fluoroc'hemistry' (1945). An eXtremely thinelectrically conductive lamina "12 'is superimposed engine transparentlariiirial't) and is s'ubjected'to a small positive potential. 'Lamina'12 maybe in the form ofa' co'nductive electron 'permeablegrid.superimposed'on the conductive grid'lamina "I2 is a'lamina I4of'photoeniis'sive material. A ray of light indicated'bythe'arrowRfwhi'eh impinges'on the 'transparent lai'nina 10, is transmittedthrough'the interstices ofthef grid and, in-turn, impinges on thephotoemissi've lanii'na 14, "exciting the photoeinissive material to anextenfpropor'tional to'th'e' intensityjof the-light ray, 'sothatthephotoemissive lamina 14 "emits electrons in proportion t'o'the'intensity of theli'ght'ra'y. Such'e'mitted electrons't'end tolgravitateor accelerateto the point in the system of hig'hef'potential. T y

Superimposed on the photoemissive lamina '1'4'isfa second electricallyconductive grid 16 similar to tli'egrid 12. A secondphotoernissivelamina '18 is superim ed on the 'grid'16. This;photoemissive la'rnina [8is 'sim at m the laminai'14. A third electrically conductive grid 0,similar to grids 12 and '16, is superim osed 'o'nthe lamina 18.Superimposed on the. grid 20 is a se'corid transparent or transliieentlamina 22, similar'to'the lamina 10 described labove. This lamina 22cojntainsactive'niaterial"the're'i'n that fluoresces when 'bo'mbardedvvith electrons, thereby transformingftheelectfons into light rays.Superimppsedon the transparent'lamina 22'is a reflecting lamina 24 whichmay "be'ia metal foil-or otherjsuitable light reflecting material.Theer'itirela'rhinate'is mounted I Fig. 2 shows'ja slightly modified'ciicuit for'the amflector wherein a resistance 40 is placed in the.icohduct or 30 connecting the grid tofthe ,positivefbatter ytei ininalin place "(if the Evariable; voltage nt'roller 'of Fig "1. Fig. 3showsfanother niijdr e circuit for'thelaififle" or, wherein theconductors zsjand 'sz areyeenneqted to he positivefter'rninal of aprimer batteries 41 ai1cl 42,wh eas the conductor 30,, iS- connected tothe 'p'os ve -t'e'riniifal of the'battery 41. Thus, 'if thepofe' 20 isvengnie pare marina rid 16" ampleybe 25fvol'ts." u I If furtheramplificatidnfjof electrons the emissive lamina lsfaii'dac c'el'era'tedby -'tlie gr1d-20is desired, they ma I be" amplified asna 'rfirmner' etthus amplified many times in the reflected-beam.

3 times through the employment of additional laminated elements eachsimilar to the laminated element comprising the laminae 18 and 20. Theincreasingly amplified electrons tend to gravitate or accelerate to apoint of higher potential as will be described hereafter.

The Zworykin and Morton book entitled Television published by John Wileyand Sons, Inc., discusses in detail numerous fluorescent andphotoemissive materials which are suitable for use, and consequently, itis not necessary to discuss such materials herein, but reference ishereby made to this book in connection with such materials.

The operation of this amflector is as follows: A ray of light R fallingon the amflector will shine through the transparent face and theinterstices of the grid 12 into the photoemissive layer 14. Lightfalling on the photoemissive material releases electrons, designatedprimary electrons, which leave the material with some velocity. Suchemitted electrons tend to gravitate or accelerate to the point of higherpotential, in this case toward the grid 28, which carries a higherpotential than the grid 30. Thus, it will be seen that a portion of thelight in passing through lamina 14 is transformed into an electron raywhich is, in effect, reversed back through grid 12 to the upper face 10and is therein converted into fluorescence.

As the electron is negatively charged, it is accelerated toward thehigher positively charged grid 12 and acquires a high velocity andenergy level. Proceeding downwardly, the remainder of the light ray Rpasses through the interstices of the center grid 16 and enters thelayer 18 of photoemissive material. Here, the photons react with thephotoemissive material and cause the emission of electrons. Theseelectrons are now accelerated downwardly by the grid 20 charged to apositive potential higher than grid 18. As a potential differencebetween the grids, at least 10 volts is desirable. Assuming that thegrid 16 is charged with a positive potential of /2 volts, then grid 18can be charged to any potential above /2 volts. Assuming, for example,that grid 18 is charged to about 102 volts, the secondary electronsemitted by the photoemissive layer 18 will be accelerated to an energylevel four times that of the primary electron, since there is four timesas much voltage used.

Passing through the grid 20, the secondary electrons expend theirkinetic energy in layer 22, causing the fluorescent material in thislayer to fluoresce, becoming converted to light. The portion of the beamof fluorescent light continues downwardly in the direction of the flowof the electrons and contacts the light reflecting surface 24. Thisfluorescent light is reflected in the opposite direction as any otherlight. After reflection, the light beam proceeds upwardly, and exactlythe same sequence takes place that occurred on the downward procession.In short, the fluorescent light proceeding upwardly into layer 18 causesthe emission of primary electrons, which are accelerated towards grid 20and bombard layer 22 where they cause the additional fluorescence. Aportion of the light given off by the fluorescence of layer 22 isconverted into electrons in layer 18 and rebounds to amplify thefluorescence of layer 22.

I The remaining portion of the light given off by layer 22 passesupwardly through layers 20, 18 and 16 into photoemissive layer 14 whereagain a portion of the light is converted into electrons. In turn, thisgreatly increased number of electrons accelerated by higher potentialgrid 12 pass into layer 10 where their large number and high energycause brilliant fluorescence. This fluorescence is an amplified lightbeam that is projected back into space from the face of layer 10. Theincident beam of light 'is In this form of amflector, it will be seenthat sever transformations of energy take place: a light beam impingingon the amflector face 10 is transformed into a beam of primaryelectrons, which are accelerated to a higher energy and are thentransformed into an amplified beam of light. The remainder of theinitial light beam that was not converted into electrons and a portionof the amplified beam are then converted into electrons, which are alsoaccelerated to a higher energy and finally transformed into an amplifiedbeam of light of an intensity many times that of the original beam oflight. Possible applications of this concept will be considered in moredetail hereinafter.

In the form of the amflector shown in Figs. 5-7, the intermediateconversion of the electrons into light prior to reflection iseliminated. In the form of the invention shown in Figs. 5-7, an outerlamina 50 is provided which is a transparent or translucent face havinggood insulating properties and highly weather-resistant. This lamina 50can be a sheet of glass or plastic, or it can be a film or lacquer orother resin applied by spraying, silk screen or other means.

Superimposed thereon is a lamina 52 which is a combined photoemissiveand fluorescent layer containing a grid 54 therein. The grid 54 can be acopper screen or other electrically conductive lamina. In the formillustrated, a copper screen is embedded in a film of resin or varnish,which plastic carries active elements classed as luminescent andfluorescent materials. If desired, separate laminations could be used toperform the photoemissive and fluorescent functions. A great many suchactive materials can be used, and the selection of the photoemissive andfluorescent composition is a matter of engineering skill. Suitablefluorescent and luminescent materials are given in Zworykin and Mortonsbook entitled Television published by John Wiley & Sons. For example, ifthe incident light is ordinary daylight, the photosensitive material toreceive the light and emit electrons might be caesium or rubidium insome form, perhaps in combination with silver. For the fluorescentmaterial, an organic material might be used such as crystallizedanthracene, or a dyestufi such as a combination of fluorescein andrhodamin. Inorganic materials can also be used, natural or synthetic. Incase an X-ray picture is required to be amplified, an entirely differentset of active materials would be selected.

Superimposed on the lamina 52 is an insulating transparent film 56 whichmay be a resin, shellac or other suitable dielectric material. Asecondary photoemissive lamina 58 containing suitable electron emissivesubstances is superimposed on the film 56. The electron emissivesubstances in the lamina 58 act to multiply the primary electrons intosecondary emitted electrons. Superimposed thereon is a thin insulatingfilm 60, and finally a metal plate 62 is superimposed.

Laminae 58, 60 and 62 act together to form a composite element. Thisform of electron multiplier is sometimes called a Thin Film FieldEmitter. The electron emitting material in lamina 58 may be contained ina suitable binding material, such as an insulating varnish or plastic.The insulating film 60 is as thin as it is possible to use with thevoltage applied, depending upon the characteristics of the material.This film must also possess a high dielectric strength and a highdielectric constant.

As shown in Fig. 5, the grid 54 is connected to the positive terminal ofa battery 64 by a conductor 66. The plate 62 is connected to thenegative terminal of the battery 64 by a conductor 68. As shown in Fig.6, the negative terminal of the battery is grounded. As shown in Fig. 7,a resistance 70 is connected between the battery 64 and the conductors66 and 68 so that the voltage can be regulated. A contact 72 connectsthe conductor 66 with the resistance 70, and a contact 74 connects theconductor 68 with the resistance 70. The contacts 72 and 74 can slide tovarious positions along the resistance. If the contact 72 is moved tothe end of the resistance, the full positive potential of the batterywill be applied to the grid 54. If the contact 74 is moved to the otherend of the resistance, the full negative potential of the battery willbe applied to the plate 62. Thus, the relative potential of grid 54 andplate 62 can be varied, one as against the other, but the actual voltageto each one can also be regulated.

The form of the invention shown in Fig. 6, wherein the negative pole ofthe battery is shown grounded, is desirable in the case of a highwaysign as shown in Fig. 8.

The operation of this form of amflector is described as follows. Thelight striking the outer lamina 50 is converted to electrons in thephotoemissive lamina 52, and the electrons are accelerated downwardlyinto the electron emissive lamina 58. Secondary electrons are emittedfrom lamina 58 which are repelled by the negative charge of plate 62 andare attracted by the positive charge of the grid 54, whereby thesecondary electrons are accelerated upwardly. These acceleratedelectrons excite fluorescence in the lamina 52, which gives oif anamplified beam of light.

In this form of. amflector it will be noted that the laminae 58, 60 and62 form a condenser. Laminae 52, 56 and 58 likewise form a condenser inseries with the first. Lamina 58 acts in a double capacity, becoming thepositive plate of the condenser 58, 60, 62 and the negative plate of thecondenser 52, 56, 58. Thus, the lamina 58 will not show a charge as awhole, whereas the lamina 52 will show a positive charge and plate 62will show a negative charge.

When operating, the lamina 58 would tend to acquire a positive chargeequal to that of lamina 52 due to the loss of electrons by balance.However, in this arrangement, this cannot take place because of theintense field created across the insulating thin film 60, which willcause electrons to migrate across into the lamina 58 when and whereneeded. This lamina 58 has semi-conductor characteristics. 7

Lamina 52 can be made in several ways. The form illustrated is alike onboth sides of thegrid wires 54. Both top and bottom sides contain thesame active materials so that fluorescence or the emission of electronscan take place either above or below the level of the grid. Thoseelectrons emitted below the grid will take an upward course due to thepowerful attraction of the positively charged grid 54. The force ofattraction is proportional to the potential of the grid. Those electronsemitted above the grid will be accelerated in a downward direction forthe same reason, and will pass through the interstices of the grid. Theelectrons accelerated upward excite fluorescence in the fluorescentmaterial present. Those accelerated downward cross the insulating film56 and enter lamina 58. The electron emissive substances contained inlamina 58 cause the secondary emission of electrons as previouslydescribed. In the arrangement described, it is possible to obtain theemission of several thousand secondary electrons for each primaryelectron.

Because of the large amplification possible, only one other acceleratingelement is shown, but if desired any number may be used in cascade. Inthis form of the invention, it will be seen that the light beam istransformed into electrons which are multiplied, and reflected by anegatively charged plate and then transformed back into amplified light.This form of the invention has a reaction time factor which may not besuitable for television usage; however, it would be suitable for amotion picture screen where the permitted time factor is comparativelylarge. Also, it would be useful as an amflection screen upon which toproject photographs. It would be extremely useful as a highway marker.

The amflectors described in Figs. 1-3 and 5-7 have many uses. Ofparticular importance is the use of this device to obtain amplifiedlight for illumination. As shown in Fig. 4, a ceiling 80 is providedwith a reflector 82 suspended in a central location surrounded by aplurality of amflector panels 84. Inside the reflector 82 is a source ofultra violet light, for example, a mercury quartz tube. The light isreflected by the reflector" 82 onto the amflectors 84 wherein the lightis amplified-for illumination of the room.

Referring to Fig. 4, the room comprising the walls" 86 may beilluminated by the amflectors 88 excited by a source of light ofsuitable wavelength located within the reflectors 90 shown near thebottom of each amflector 88.

Utilizing these forms of the invention, it is possible to attain severalhundred lumens of visible light per watt.

The form of the invention shown in Fig. 8 illustrates the use of theamflectors in conjunction with highway signs and markers wherein thelight from the headlights of approaching automobiles can be amplified tointensify the light reflected back to the automobile. 7

it will be obvious to those skilled in the art that various changes maybe made without departing from thespirit of the invention and thereforethe invention is not limited to what is shown in the drawings anddescribed in the specification but only as indicated in the appendedclaims.

What is claimed is:

1. In a light amplifying and reflecting system, the combination of alaminated structure of contacting laminae including a lamina of electronsensitive and light-emissive material, a lamina of light sensitive andelectron-emissive material, a lamina of an electrically conducting material, a source of positive potential connected to said lamina ofelectrically conducting material to maintain a positive charge thereon,a thin insulating lamina, a lamina of electron-emissive material havingthe characteristic of emitting more than one electron for each electronimpinging thereon, a thin lamina of insulating material, a metalliclamina, and a source of negative potential connected to said metalliclamina, said lamina being arranged in the order specified, whereby abeam of light striking said structure is converted into electrons, thenumber of electrons is multiplied and reversed in direction, and theelectrons are converted into an amplified beam of light which is emittedfrom the structure.

2. In a light amplifying and reflecting system in accordance with claim1, wherein said electrically conducting lamina is an electron permeablegrid, and wherein said electron sensitive and light emissive materialand said light sensitive and electron-emissive material are disposed inthe interstices of said grid whereby said laminae are substantiallycoextensive.

3. In a light amplifying and reflecting system, the combination of alaminated structure of contacting laminae arranged in the orderspecified including an outer lamina of electron sensitive and lightemissive material, a lamina of an electrically conducting material, asource of positive potential connected to said lamina of electricallyconducting material to maintain a positive charge thereon, and a laminaof light sensitive and electron emissive material, whereby a beam oflight entering said system is converted into electrons in said lightsensitive and electron emissive lamina, said electrons are acceleratedin the opposite direction by said positively charged conducting laminathereabove, and said accelerated electrons are converted into anamplified beam of light in said outer lamina.

4. In a light amplifying and reflecting system, the combination of alaminated structure of contacting laminae arranged in the order specificincluding an outer lamina of electron sensitive and light emissivematerial, a lamina of an electrically conducting material, a source ofpositive potential connected to said lamina of electrically conductingmaterial to maintain a positive charge thereon, a lamina of lightsensitive and electron emissive material, and specular means forreflecting light, whereby a light beam entering said system is partiallyconverted into electrons in said light sensitive and electron emissivelamina, said electrons are accelerated in the opposite direction by saidpositive conducting lamina 7 outwardly thereof, and said acceleratedelectrons are converted into an amplified beam of-light in said outerlamina,"and the remaining light passing through said system is reflectedin the opposite direction by the reflecting means and is amplified inthe same manner previously described in returning through the system.

5. In a light amplifying and reflecting system, the combination of alaminated structure of contacting laminae arranged in the orderspecified including an outer lamina of electron sensitive and lightemissive material, a first lamina of an electrically conductingmaterial, a source of positive potential connected to said lamina ofelectrically conducting material to maintain a positive charge thereon,a lamina of light sensitive and electron emissive material, a secondlamina of electrically conducting material, a source of positivepotential connected to said lamina of electrically conducting materialto maintain a positive charge thereon, a lamina of light sensitive andelectron emissive material, a third lamina of an electrically conductingmaterial, a source of positive potential connected to said lamina ofelectrically conducting material to maintain a positive charge thereon,said second lamina of electrically conducting material having a lowerpositive charge than the first and third said laminae, a lamina ofelectron sensitive and light emissive material, and specular means forreflecting light, whereby light entering said system is converted intoelectrons in said light sensitive and electron emissive laminae, saidelectrons being accelerated in the direction of the nearest higherpositively charged lamina, said accelerated electrons being convertedinto an amplified beam of light, the innermost amplified beam of lightbeing reflected outwardly and being further amplified in passingoutwardly through said laminae.

6. In a light amplifying and reflecting system, the combination of meansfor transforming a beam of light into a beam of electrons, means foraccelerating said beam of electrons, means for converting saidaccelerated beam of electrons into an amplified beam of light, means forreflecting said amplified beam of light back through said previouslydefined means whereby a portion of said amplified beam of light is againconverted into electrons, said electrons are accelerated, and saidaccelerated electrons are converted into an amplified beam of light.

7. In a light amplifying and reflecting system, the combination of meansfor transforming a beam of light into a beam of electrons, means foraccelerating said beam of electrons, means for reversing the directionof said beam of electrons back through said previously defined means andmeans for transforming said beam of electrons into an amplified beam oflight which passes from the system in the direction opposite to thedirection of the original beam of light.

8. A method of reflecting and amplifying a beam of light comprisingtransforming'said beam of light into a beam of electrons, acceleratingthe beam of electrons, transforming the accelerated beam of electronsinto an amplified beam of light, reflecting the amplified beam of lightin a direction opposite to the direction of the original beam of light,transforming the amplified beam of light into an amplified beam ofelectrons, reaccelerating the amplified beam of electrons, andtransforming the reaccelerated beam of electronsinto a reamplified beamof lightwhich is emitted in a direction opposite to the direction of theoriginal beam of light.

9. A method of reflecting and amplifying a beam of light comprisingtransforming said beam of light into a beam of electrons, amplifying thebeam of electrons into an amplified beam of electrons, accelerating theamplified beam of electrons in a direction opposite to the direction ofthe original beam of light, transforming the accelerated amplified beamof electrons into an amplified beam of light which is emitted in adirection opposite to the direction of the original beam of light whichhas now been amplifiedQ 10. In a light amplifying and reflecting system,the combination of a laminated structure of contacting laminae arrangedin the order specified, including a lamina of light sensitive andelectron emission material, a lamina of electrically conductingmaterial, a source of positive potential connected to said lamina ofelectrically conducting material to maintain a positive charge thereon,a lamina of electron sensitive and light emissive material, and specularmeans for reflecting light, whereby light entering said system isconverted into electrons, said electrons are accelerated, theaccelerated electrons being converted into an amplified beam of lightwhich is reflected in the opposite direction and emitted from thesystem.

11. In a light amplifying and reflecting system in accordance with claim1, wherein said lamina of electron emissive material has semi-conductingproperties.

References Cited in the file of this patent UNITED STATES PATENTS

